Solve One Step Subtraction Equations

Main idea of one step subtraction equations

A one step subtraction equation is when a number is being subtracted from a variable We solve by using the inverse operation addition That is why we use addition to isolate the variable

Definition of equation

A math sentence with an equal sign that shows two sides are the same

Definition of inverse operation

An operation that undoes another operation For subtraction the inverse operation is addition

Example 1 Solve x - 10 = 30

Think what number minus 10 equals 30 40 - 10 = 30 so x = 40 Check 40 - 10 = 30 true

Remember this about one step subtraction equations

To solve add the number to both sides Always check your answer by substituting it back into the original equation

Why negative four and positive four equals zero

Negative four means you take away 4 Positive four means you add back 4 When you do both they cancel out -4 + 4 = 0 Think owe 4 dollars pay back 4 dollars now you owe 0 So in x - 4 + 4 the -4 and +4 disappear leaving just x

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Solve One Step Subtraction Equations 9 12 25 4